I just want to know what octane to use because right now i use 93 and i'm getting system rich. Here is my mod:

milled head .020
5 angle valve
regrined cams and gears

compression test: 175 : 175 : 175 : 175

I'm also going to be running nitrous soon. but do i need 93 now or could i use 87 or 89?

If you don't have nitrous or turbo, USE the cheapest gas (87-89 octance). I'm not sure about this theory here, but if you use a hi-octane gas, your not burning all the fuel mixtures. Probable cause of you going rich. Although there are other factors of going rich. Our engines are designed to run with 'regular' gas. Somebody here knows more about this I'm sure!!!!

yeah, the ECU is designed for 87 octane gas. if you use any higher (without a turbo, high compression, or nitrous) you are just wasting you money.

I know but with my head milled I should have like 10.1 to 1, right?

87 should be fine.

i dont know.. i have a stock motor with just a iceman and using the one range hotter plugs /magnecore wires..

i use 93 as the higher octane reduces early detonation and that causes engine probelms if the fuel detonates too early.. the brain may be set up for 87 but they have MAP sensors and they will adjust to the fuel being used...

i even used 93 in my Yugo (first car) and it got great performance :P

thats how i feel..

i think that with high compression you should go ahead and go the safe route and use 93 octane, but you should wait until some of the all motor guys respond

You need an S-AFC to lean it out. Also, you must run at least 93 octane when you use the nitrous.